I. Technical Field
The present invention relates to a wheel bearing device, a method of assembling the wheel bearing device, an assembly configured by the wheel bearing device and a drive shaft, and a method of assembling the assembly.
II. Description of the Related Art
As shown in FIG. 11, a drive shaft that transmits power from an engine to a driving wheel has a configuration in which an outboard-side (an outer side of a vehicle when assembled to the vehicle) fixed constant velocity universal joint 104 and an inboard-side (an inner side of the vehicle when assembled to the vehicle) sliding-type constant velocity universal joint (not shown) are connected by an intermediate shaft (not shown). The outboard-side fixed constant velocity universal joint 104 is connected to a hub 102 that is supported by a wheel bearing device such as to rotate freely.
A so-called third generation wheel bearing device includes the hub 102, the constant velocity universal joint 104, and an outer member 105. The hub 102 has a flange 101 extending in an outward radial direction. An outer joint member 103 of the constant velocity universal joint 104 is fixed to the hub 102. The outer member 105 configures a portion of a wheel bearing and is disposed on an outer circumferential side of the hub 102.
The constant velocity universal joint 104 includes the outer joint member 103, an inner joint member 108, a ball 109, and a cage 110. The inner joint member 108 is disposed within a bowl-shaped section 107 of the outer joint member 103. The ball 109 is disposed between the inner joint member 108 and the outer joint member 103. The cage 110 holds the ball 109. A spline section 111 is formed on an inner circumferential surface of a center hole in the inner joint member 108. An end section spline section of a shaft (not shown) is inserted into the center hole. As a result, the spline section 111 on the inner joint member 108 side and the spline section on the shaft side are engaged.
The hub 102 has a cylindrical section 113 and the flange 101. A short, cylindrical pilot section 115 is provided on an outer end surface (counter-joint side end surface) of the flange 101 such as to project from the outer end surface. A wheel and a brake rotor (not shown) are mounted on the pilot section 115. The pilot section 115 is configured by a first section 115a having a large diameter and a second section 115b having a small diameter. The brake rotor is fitted onto the first section 115a, and the wheel is fitted onto the second section 115b. 
A small diameter stepped section 116 is provided on an outer circumferential surface of the bowl-shaped section 107 side end section of the cylindrical section 113. An inner ring 117 configuring an inner member of the wheel bearing is fitted onto the small diameter stepped section 116. A first inner raceway surface 118 is provided on an outer circumferential surface of the cylindrical section 113 of the hub 102, near the flange. A second inner raceway surface 119 is provided on an outer circumferential surface of the inner ring 117. A bolt mounting hole 112 is provided in the flange 101 of the hub 102. A hub bolt 135 used to fix the wheel and the brake rotor to the flange 101 is inserted into the bolt attaching hole 112.
Double-row outer raceway surfaces 120 and 121 are provided on an inner periphery of the outer member 105 of the wheel bearing. A flange (vehicle body attaching flange) 132 is provided on an outer periphery of the outer member 105. The first outer raceway surface 120 of the outer member 105 and the first inner raceway surface 118 of the hub 102 oppose each other. The second raceway surface 121 of the outer member 105 and the second inner raceway surface 119 of the inner ring 117 oppose each other. Rolling elements 122 are interposed between the outer and inner raceway surfaces.
A stem shaft 123 of the outer joint member 103 is inserted into the cylindrical section 113 of the hub 102. A screw section 124 is formed on an end section the stem shaft 123 in the counter-bowl-shaped section. A spline section 125 is formed between the screw section 124 and the bowl-shaped section 107. A spline section 126 is also formed on an inner circumferential surface (inner diameter surface) of the cylindrical section 113 of the hub 102. When the stem shaft 123 is inserted into the cylindrical section 113 of the hub 102, the spline section 125 on the stem shaft 123 side and the spline section 126 on the hub 102 side become engaged.
As described in Japanese Patent Laid-open Publication No. 2004-270855, a nut member 127 is screwed onto the screw section 124 of the stem shaft 123 projecting from the cylindrical section 113, and the hub 102 and the outer joint member 103 are connected. At this time, an inner end surface (rear surface) 128 of the nut member 127 and an outer end surface 129 of the cylindrical section 113 come into contact. In addition, an end surface 130 of the bowl-shaped section 107 on a shaft section side and an outer end surface 131 of the inner ring 117 come into contact. In other words, as a result of the nut member 127 being tightened, the hub 102 is sandwiched between the nut member 127 and the bowl-shaped section 107 with the inner ring 117 therebetween. As a result, the outer joint member 107 and the hub 102 are positioned in an axial direction, and a predetermined preload is applied to the wheel bearing device.    Patent Document 1: Japanese Patent Laid-open Publication No. 2004-270855